Many systems and instruments for measuring selected properties of an oil have been described in the art. Measuring systems measuring physical properties of oils, such as viscosity are standard in the art and are used widely for determine the quality of an oil. In particular when transporting large amount of an oil from one container to another it is often desired to make sure that the transported oil has the desired quality.
WO 05021419 describe a vehicle misfuelling alert apparatus for use with a fuel pump having at least one fuel nozzle. The apparatus includes a transmitter for transmitting a data signal and positioned on the bodywork of a vehicle adjacent the fuel tank inlet of the vehicle. A receiver is positioned on the fuel nozzle adjacent the handle portion. The data signal contains a unique fuel code which represents the type of fuel required by the vehicle. The receiver has a predetermined set of stored data that represents the type of fuel dispensed by the fuel nozzle. When a motorist presents the fuel nozzle to the fuel tank inlet, the receiver will receive the data signal transmitted by the transmitter and alerts the motorist by means of an indicator if the data signal does not match the stored data (i.e. if the fuel dispensed by the fuel nozzle is not the type of fuel required by the vehicle).
This misfuelling alert apparatus does not measure any property of the fuel, but compare only an fuel type identification signal transmitted from the vehicle to the fuel dispenser to identify if this type of fuel is dispensed from this fuel dispenser. In practice such an alert apparatus is only useful is specific situations, such as situation where possibly variations within the type of fuel is not relevant or not existing
A similar fuel dispensing system is disclosed in U.S. Pat. No. 5,722,469. This system additionally comprises a contamination detection device which during fuel loading measures the specific gravity of the fuel to thereby detect possibly contaminations.
U.S. Pat. No. 4,704,898 discloses an apparatus for measuring the viscosity of a liquid. The viscosity meter is determining the viscosity using an oscillating damping system and the viscosity is determined by way of a comparison of the energy absorbed with the energy absorbed in a liquid of known viscosity. The viscosity meter disclosed may e.g. be utilized in order to monitor the viscosity of a liquid which is required to be delivered to a customer with given quality features, e.g. bunker fuel for delivering to a ship. The viscosity meter may be arranged within the bunker pipe 58 for measuring the viscosity of the fuel flowing through the bunker pipe 58.
The above described prior art systems are often suitable when measuring on general homogenous oils, or where the composition of the oil is relatively well known, However, many types of oil are in practice a mixture of hydrocarbons of different sizes and a plurality of other constituents, such as inorganic components, and/or more or less dispersed particles. The viscosity may be very high to very low for the same oil batch to be transported from one container to another, and in general it has been found that the viscosity cannot stand alone for determinate the oil quality.
Many of these types of oils are very inhomogeneous, and the composition and quality thereof cannot be measured by simply withdrawing a sample and sending it to a text lab.
Within the art of bunker fuel, sample collection has become an important discipline, due to the difficulties in collecting representative samples from a bunker fuel under loading. The general accepted sampler systems are systems based on sampling small amounts during loading and pooling the sample for quality test. The most used samplers are drip samplers.
The object of the invention is to provide a measuring system which provide an effective and fast method of determining quality of an oil irrespectively of the inhomogeneity of the oil